First you need to stop the running 5.5. version: Make a backup of your mariadb datafolder: Then remove the 5.5 version: Download the MariaDB Package Repository Setup Script: curl -LO Then make it executable and run it: It will then create a /etc/yum.repos.d/mariadb.repo file with content adjusted for your system. In our system it

We have a multiuser Machform PHP application running on a Redhat 7 Linux server with Apache webserver and MariaDB database. In a specific form after page 3, accessing this URI: confirm.php?id=NNNNNNNN&mf_page_from=3 where NNNNNNNN is the id number of the form, The following error message appears: SQL: [671] select A.element_id, A.option_id, (select if(B.element_matrix_parent_id=0,A.option, (select C.`option` from